In broadcast environments, such as a satellite broadcast environment, data signals are typically received by an antenna, dish, or other signal receiving mechanism. A transponder is a frequency band or channel of a broadcast signal. Satellites transmit data using multiple transponders (or channels), such as thirty-two transponders. The multiple transponders are divided into a left hand polarity and a right hand polarity such that sixteen transponders each include the two polarities.
The received signals are initially processed by a first unit which includes a receiving antenna or dish, and a Low Noise Block Feed component (LNBF). This first unit may also be referred to as an “outdoor unit” or as an “outdoor tuning device”. The receiving antenna or dish focuses the two polarities of a transmitted satellite signal to the LNBF. The LNBF amplifies the weak satellite signal and converts the signal from the KU band (approximately 12 GHz) to the L band (approximately 1.5 GHz) so that the signal can be processed with conventional electronic processing components. The LNBF also separates the two polarities of the satellite signal. This first unit transmits the signal to a second device, such as an Integrated Receiver Decoder (IRD) connected to a television, an audio/video system, or similar device. This second device may also be referred to as an “indoor receiver”.
In a conventional satellite receiver system, the IRD (or indoor unit) places a direct current (DC) power on the coaxial cable that connects the IRD and the outdoor unit. This is used to power the LNBF and to signal the LNBF as to which polarity is to be placed on the coaxial cable. The DC power can be switched by the IRD between, for example, thirteen volts and eighteen volts to identify the appropriate polarity.
The IRD has a tuning device that can tune to one of the sixteen transponders and retrieve the associated data from the signal. The data may contain information for up to ten television shows and include both audio information and video information. Specific selection of a television show is performed with logic or by computer programs that can, for example, select the audio/video data packets for a particular television show.
Each tuner of the IRD tuning device can tune to one transponder of one polarity from one satellite. If a particular system has multiple tuners, then multiple transponders received from one or more satellites can be tuned simultaneously. Conventional systems use separate communication links, such as separate coaxial cables or other conductors, to communicate signals to multiple tuners. For example, in a system with four tuners, four coaxial cables are run in parallel between the LNBF and the IRD.
Attempts to transmit multiple transponders that may be of separate polarity or received from multiple satellites across a common communication link are likely to result in crosstalk and/or other signal corruption between the multiple transponders. The crosstalk and/or other signal corruption is caused when transmitting signals having different strengths via the same communication link. One or more stronger transponders (or signal components) will dominate the weaker transponders. Thus, to communicate multiple transponders between two devices, a conventional system must operate with the signal corruption problems or implement separate communication links for signals associated with each transponder.
Accordingly, there is a need for systems and methods that adjust the signal strength of one or more signal components to reduce crosstalk and other signal corruption between the signal components.